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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
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2 * |
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3 * LibTomCrypt is a library that provides various cryptographic |
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4 * algorithms in a highly modular and flexible manner. |
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5 * |
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6 * The library is free for all purposes without any express |
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7 * guarantee it works. |
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8 * |
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9 * Tom St Denis, [email protected], http://libtomcrypt.org |
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10 */ |
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11 |
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12 /* RC5 code by Tom St Denis */ |
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13 |
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14 #include "mycrypt.h" |
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15 |
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16 #ifdef RC5 |
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17 |
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18 const struct _cipher_descriptor rc5_desc = |
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19 { |
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20 "rc5", |
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21 2, |
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22 8, 128, 8, 12, |
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23 &rc5_setup, |
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24 &rc5_ecb_encrypt, |
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25 &rc5_ecb_decrypt, |
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26 &rc5_test, |
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27 &rc5_keysize |
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28 }; |
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29 |
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30 static const ulong32 stab[50] = { |
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31 0xb7e15163UL, 0x5618cb1cUL, 0xf45044d5UL, 0x9287be8eUL, 0x30bf3847UL, 0xcef6b200UL, 0x6d2e2bb9UL, 0x0b65a572UL, |
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32 0xa99d1f2bUL, 0x47d498e4UL, 0xe60c129dUL, 0x84438c56UL, 0x227b060fUL, 0xc0b27fc8UL, 0x5ee9f981UL, 0xfd21733aUL, |
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33 0x9b58ecf3UL, 0x399066acUL, 0xd7c7e065UL, 0x75ff5a1eUL, 0x1436d3d7UL, 0xb26e4d90UL, 0x50a5c749UL, 0xeedd4102UL, |
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34 0x8d14babbUL, 0x2b4c3474UL, 0xc983ae2dUL, 0x67bb27e6UL, 0x05f2a19fUL, 0xa42a1b58UL, 0x42619511UL, 0xe0990ecaUL, |
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35 0x7ed08883UL, 0x1d08023cUL, 0xbb3f7bf5UL, 0x5976f5aeUL, 0xf7ae6f67UL, 0x95e5e920UL, 0x341d62d9UL, 0xd254dc92UL, |
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36 0x708c564bUL, 0x0ec3d004UL, 0xacfb49bdUL, 0x4b32c376UL, 0xe96a3d2fUL, 0x87a1b6e8UL, 0x25d930a1UL, 0xc410aa5aUL, |
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37 0x62482413UL, 0x007f9dccUL |
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38 }; |
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39 |
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40 #ifdef CLEAN_STACK |
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41 static int _rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) |
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42 #else |
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43 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) |
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44 #endif |
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45 { |
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46 ulong32 L[64], *S, A, B, i, j, v, s, t, l; |
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47 |
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48 _ARGCHK(skey != NULL); |
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49 _ARGCHK(key != NULL); |
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50 |
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51 /* test parameters */ |
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52 if (num_rounds == 0) { |
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53 num_rounds = rc5_desc.default_rounds; |
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54 } |
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55 |
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56 if (num_rounds < 12 || num_rounds > 24) { |
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57 return CRYPT_INVALID_ROUNDS; |
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58 } |
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59 |
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60 /* key must be between 64 and 1024 bits */ |
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61 if (keylen < 8 || keylen > 128) { |
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62 return CRYPT_INVALID_KEYSIZE; |
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63 } |
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64 |
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65 skey->rc5.rounds = num_rounds; |
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66 S = skey->rc5.K; |
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67 |
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68 /* copy the key into the L array */ |
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69 for (A = i = j = 0; i < (ulong32)keylen; ) { |
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70 A = (A << 8) | ((ulong32)(key[i++] & 255)); |
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71 if ((i & 3) == 0) { |
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72 L[j++] = BSWAP(A); |
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73 A = 0; |
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74 } |
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75 } |
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76 |
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77 if ((keylen & 3) != 0) { |
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78 A <<= (ulong32)((8 * (4 - (keylen&3)))); |
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79 L[j++] = BSWAP(A); |
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80 } |
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81 |
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82 /* setup the S array */ |
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83 t = (ulong32)(2 * (num_rounds + 1)); |
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84 XMEMCPY(S, stab, t * sizeof(*S)); |
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85 |
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86 /* mix buffer */ |
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87 s = 3 * MAX(t, j); |
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88 l = j; |
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89 for (A = B = i = j = v = 0; v < s; v++) { |
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90 A = S[i] = ROL(S[i] + A + B, 3); |
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91 B = L[j] = ROL(L[j] + A + B, (A+B)); |
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92 if (++i == t) { i = 0; } |
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93 if (++j == l) { j = 0; } |
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94 } |
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95 return CRYPT_OK; |
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96 } |
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97 |
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98 #ifdef CLEAN_STACK |
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99 int rc5_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey) |
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100 { |
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101 int x; |
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102 x = _rc5_setup(key, keylen, num_rounds, skey); |
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103 burn_stack(sizeof(ulong32) * 122 + sizeof(int)); |
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104 return x; |
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105 } |
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106 #endif |
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107 |
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108 #ifdef CLEAN_STACK |
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109 static void _rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key) |
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110 #else |
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111 void rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key) |
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112 #endif |
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113 { |
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114 ulong32 A, B, *K; |
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115 int r; |
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116 _ARGCHK(key != NULL); |
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117 _ARGCHK(pt != NULL); |
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118 _ARGCHK(ct != NULL); |
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119 |
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120 LOAD32L(A, &pt[0]); |
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121 LOAD32L(B, &pt[4]); |
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122 A += key->rc5.K[0]; |
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123 B += key->rc5.K[1]; |
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124 K = key->rc5.K + 2; |
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125 |
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126 if ((key->rc5.rounds & 1) == 0) { |
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127 for (r = 0; r < key->rc5.rounds; r += 2) { |
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128 A = ROL(A ^ B, B) + K[0]; |
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129 B = ROL(B ^ A, A) + K[1]; |
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130 A = ROL(A ^ B, B) + K[2]; |
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131 B = ROL(B ^ A, A) + K[3]; |
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132 K += 4; |
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133 } |
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134 } else { |
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135 for (r = 0; r < key->rc5.rounds; r++) { |
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136 A = ROL(A ^ B, B) + K[0]; |
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137 B = ROL(B ^ A, A) + K[1]; |
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138 K += 2; |
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139 } |
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140 } |
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141 STORE32L(A, &ct[0]); |
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142 STORE32L(B, &ct[4]); |
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143 } |
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144 |
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145 #ifdef CLEAN_STACK |
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146 void rc5_ecb_encrypt(const unsigned char *pt, unsigned char *ct, symmetric_key *key) |
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147 { |
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148 _rc5_ecb_encrypt(pt, ct, key); |
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149 burn_stack(sizeof(ulong32) * 2 + sizeof(int)); |
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150 } |
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151 #endif |
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152 |
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153 #ifdef CLEAN_STACK |
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154 static void _rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key) |
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155 #else |
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156 void rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key) |
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157 #endif |
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158 { |
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159 ulong32 A, B, *K; |
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160 int r; |
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161 _ARGCHK(key != NULL); |
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162 _ARGCHK(pt != NULL); |
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163 _ARGCHK(ct != NULL); |
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164 |
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165 LOAD32L(A, &ct[0]); |
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166 LOAD32L(B, &ct[4]); |
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167 K = key->rc5.K + (key->rc5.rounds << 1); |
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168 |
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169 if ((key->rc5.rounds & 1) == 0) { |
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170 K -= 2; |
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171 for (r = key->rc5.rounds - 1; r >= 0; r -= 2) { |
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172 B = ROR(B - K[3], A) ^ A; |
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173 A = ROR(A - K[2], B) ^ B; |
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174 B = ROR(B - K[1], A) ^ A; |
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175 A = ROR(A - K[0], B) ^ B; |
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176 K -= 4; |
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177 } |
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178 } else { |
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179 for (r = key->rc5.rounds - 1; r >= 0; r--) { |
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180 B = ROR(B - K[1], A) ^ A; |
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181 A = ROR(A - K[0], B) ^ B; |
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182 K -= 2; |
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183 } |
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184 } |
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185 A -= key->rc5.K[0]; |
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186 B -= key->rc5.K[1]; |
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187 STORE32L(A, &pt[0]); |
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188 STORE32L(B, &pt[4]); |
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189 } |
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190 |
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191 #ifdef CLEAN_STACK |
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192 void rc5_ecb_decrypt(const unsigned char *ct, unsigned char *pt, symmetric_key *key) |
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193 { |
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194 _rc5_ecb_decrypt(ct, pt, key); |
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195 burn_stack(sizeof(ulong32) * 2 + sizeof(int)); |
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196 } |
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197 #endif |
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198 |
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199 int rc5_test(void) |
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200 { |
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201 #ifndef LTC_TEST |
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202 return CRYPT_NOP; |
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203 #else |
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204 static const struct { |
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205 unsigned char key[16], pt[8], ct[8]; |
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206 } tests[] = { |
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207 { |
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208 { 0x91, 0x5f, 0x46, 0x19, 0xbe, 0x41, 0xb2, 0x51, |
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209 0x63, 0x55, 0xa5, 0x01, 0x10, 0xa9, 0xce, 0x91 }, |
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210 { 0x21, 0xa5, 0xdb, 0xee, 0x15, 0x4b, 0x8f, 0x6d }, |
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211 { 0xf7, 0xc0, 0x13, 0xac, 0x5b, 0x2b, 0x89, 0x52 } |
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212 }, |
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213 { |
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214 { 0x78, 0x33, 0x48, 0xe7, 0x5a, 0xeb, 0x0f, 0x2f, |
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215 0xd7, 0xb1, 0x69, 0xbb, 0x8d, 0xc1, 0x67, 0x87 }, |
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216 { 0xF7, 0xC0, 0x13, 0xAC, 0x5B, 0x2B, 0x89, 0x52 }, |
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217 { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 } |
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218 }, |
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219 { |
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220 { 0xDC, 0x49, 0xdb, 0x13, 0x75, 0xa5, 0x58, 0x4f, |
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221 0x64, 0x85, 0xb4, 0x13, 0xb5, 0xf1, 0x2b, 0xaf }, |
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222 { 0x2F, 0x42, 0xB3, 0xB7, 0x03, 0x69, 0xFC, 0x92 }, |
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223 { 0x65, 0xc1, 0x78, 0xb2, 0x84, 0xd1, 0x97, 0xcc } |
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224 } |
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225 }; |
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226 unsigned char tmp[2][8]; |
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227 int x, y, err; |
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228 symmetric_key key; |
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229 |
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230 for (x = 0; x < (int)(sizeof(tests) / sizeof(tests[0])); x++) { |
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231 /* setup key */ |
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232 if ((err = rc5_setup(tests[x].key, 16, 12, &key)) != CRYPT_OK) { |
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233 return err; |
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234 } |
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235 |
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236 /* encrypt and decrypt */ |
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237 rc5_ecb_encrypt(tests[x].pt, tmp[0], &key); |
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238 rc5_ecb_decrypt(tmp[0], tmp[1], &key); |
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239 |
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240 /* compare */ |
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241 if (memcmp(tmp[0], tests[x].ct, 8) != 0 || memcmp(tmp[1], tests[x].pt, 8) != 0) { |
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242 return CRYPT_FAIL_TESTVECTOR; |
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243 } |
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244 |
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245 /* now see if we can encrypt all zero bytes 1000 times, decrypt and come back where we started */ |
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246 for (y = 0; y < 8; y++) tmp[0][y] = 0; |
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247 for (y = 0; y < 1000; y++) rc5_ecb_encrypt(tmp[0], tmp[0], &key); |
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248 for (y = 0; y < 1000; y++) rc5_ecb_decrypt(tmp[0], tmp[0], &key); |
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249 for (y = 0; y < 8; y++) if (tmp[0][y] != 0) return CRYPT_FAIL_TESTVECTOR; |
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250 } |
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251 return CRYPT_OK; |
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252 #endif |
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253 } |
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254 |
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255 int rc5_keysize(int *desired_keysize) |
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256 { |
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257 _ARGCHK(desired_keysize != NULL); |
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258 if (*desired_keysize < 8) { |
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259 return CRYPT_INVALID_KEYSIZE; |
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260 } else if (*desired_keysize > 128) { |
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261 *desired_keysize = 128; |
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262 } |
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263 return CRYPT_OK; |
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264 } |
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265 |
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266 #endif |
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267 |
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268 |
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269 |
